Process of interacting hydrocarbons with oxygen



E. BARTHOLOME ETAL 2,862,984

Deg. 2, 1958 PROCESS OF INTERACTI NG HYDROCARBONS WITH OXYGEN Filed Sept. 20. 1955 2 Sheets-Sheet 1 FIG! INVENTORS: ERNST BARTHOLOME ERWIN LEHRER HELMUT NONNENMACHER OTTO FREY BY Q4 ATT'YS 2, 1958 E. BARTHOLOME EI'AL 2,

PROCESS OF INTERACTING HYDROCARBONS WITH OXYGEN Filed Sept. 20. 1955 2 Sheets-SfieetZ r' A 2,862,984 Ice Patented Dec. 2, 1958 PROCESS OF INTERACTING HY DROCARBONS WITH OXYGEN Application September 20, 1955, Serial No. 535,326

Claims priority, application Germany September 22, 1954 9 Claims. (Cl. 260-679) This invention relates to a process of interacting hydrocarbons, in particular, gaseous saturated aliphatic hydrocarbons with oxygen. More particularly, the invention concerns'the reaction of a hydrocarbon with such an amount of oxygen which is insufficient for the complete combustion of the hydrocarbons.

It is well known that hydrocarbons may be reacted with a limited amount of oxygen which is insuflicient for the complete combustion of the hydrocarbons, for instance, in order to manufacture acetylene or mixtures of carbon monoxide and hydrogen. Such processes are often carried out by preheating separately the initial gases, mixing them in a mixing chamber, and then introducing this mixture into a reaction chamber wherein the interaction takes place with or without the formation of a flame.

A particular difficulty of these reactions consists in the fact that the gases to be reacted must be mixed under such conditions that they react immediately in the reaction chamber or reaction zone while, on the other hand, an interaction in the mixing chamber or mixing zone must be avoided in order to be able to operate continuously and to obtain a high yield.

It is, however, even with great care, sometimes impossible to avoid the occurrence of premature reactions in the mixing zone. In such an event, the oxygen supply is stopped whereby the reaction is interrupted in the mixing zone and also in the reaction zone.

It is an object of this invention therefore to overcome these difliculties and to provide an improved process for the interaction of hydrocarbons with a limited amount of oxygen.

Another object is to provide a process for interrupting premature interactions of mixtures of a hydrocarbon and a limited amount of oxygen which is insuflicient for the complete combustion of the hydrocarbon in the mixing chamber or mixing zone without interrupting the interaction of the hydrocarbon with the oxygen in the reaction zone or reaction chamber.

These and other objects and advantages which will be apparent from a more detailed description of the invention are accomplished by introducing into the mixing chamber or mixing zone for a short period of time, an inert gas when and if an interaction of the gases to be mixed takes place in the mixing chamber or mixing zone. By the introduction of the inert gas, the interaction of the gas mixture is stopped without interrupting the reaction in the reaction chamber or reaction zone. The inert gases are particularly eflicient if they are added to the oxygen stream before the oxygen stream enters into the mixing zone.

The particular merit of this invention consists in the fact that the interaction between the hydrocarbon and the oxygen can be performed continuously and that the reaction mixture is diluted only for a short time by an inert gas, the process, therefore, having ahigher yield. Such a procedure is advantageous against the discontinuous method described before wherein the oxygen supply is temporarily completely interrupted, and it is also advantageous against a process with a continuous dilution of the reaction mixture by permanently adding a. corresponding amount of an inert gas to the reaction mixture or by performing the reaction in the absence of an inert gas but under reduced pressure. 7

In order to interrupt a reaction of the gas mixture in the mixing zone, a relatively strong blow of the inert gas but only for a short period of time is required. As a rule, at least from 10 to by volume of the inert gas with reference to the volume of the oxygen are used. Advantageously, the amount of inert gas should be even higher, for instance, 40% or about 100% by volume with reference to the volume of the oxygen. While using such an amount of inert gas, premature interactions in the mixing zone are stopped within a few minutes, mostly Within less than one minute. Suitable inert gases are, for instance, steam, nitrogen or carbon dioxide. As a rule, the process of this invention is performed under atmospheric pressure but higher or lower pressures may also be used.

The invention is of particular interest for the interaction of oxygen with methane or other saturated gaseous aliphatic hydrocarbons or gas mixtures containing such hydrocarbons, the lower aliphatic hydrocarbons being especially important. r

According to a particular advantageous embodiment of the invention, the introduction of the inert gas into the mixing zone is automatically coupled with a signal or t a device which indicatesthe occurrence of premature reand thus opens the electrically-actuated valve 9.

actions in the mixing zone. Such a signal may be released, for instance, by the increase of the pressure or of the temperature in the mixing zone.

The following examples are given in order to illustrate but not to limit the invention.

Example 1 In a first preheater 1800 cubic meters measured at normal temperature and pressure (N. T. P.) of methane per hour and in a second preheater 1050 cubic-meters (N. T. P.) of oxygen per hour are heated to 600 C. The hot gases are fed to a mixer of the type illustrated in Figure l, the methane entering through line 1 and the oxygen entering through line 2. The gases meet at point 3 and are mixed in the mixing chamber 4. Through the parallel channels 5 the gas mixture passes into the reaction chamber 6 where the oxygen and the methane react with flame formation. The reaction gases are cooled by injecting water through nozzles 7. The gas mixture obtained with a yield of 3400 cubic meters per hour (N.T.P.) contains about 8.5% of acetylene.

In normal operation the pressure will be lower at the mixing point 3'than at the end of the mixing chamber 4. However, if the mixture of oxygen and methane comes to ignite already in chamber 4, the pressure becomes higher at point 3 than at the end of chamber 4. As a result, the differential manometer 8 which is connected to chamber 3 andlchamber 4 closes an electric current Y valve 9 nitrogen is allowed to pass through line 10 into the oxygen supply pipe 2 and thence into the mixing chamber 4 where, as a result, the flame reaction is subdued. As soon as the flame has become extinguished, the initial pressures are set up again and the valve 9 is closed. The flame only takes about 2 seconds to become extinguished, the quantity of nitrogen needed being about 250 liters. The said flame extinguishing regulation will not aflect the flame reaction in chamber 6 to any notable extent.

Example 2 A further embodiment of our invention will now be described with reference to Fig. 2 of the accompanying awin 2 cu smete PF hQuxt Of 9 9. YE sa (m han c n n bw 39% b Mel??? WW9 he b e sa urated wit st am at 9 r fed 3 P h a t o l 1 nd 46 ub me er e 1 4? lT-"R of oxy e w h have a so. s n Satu d w th st m at a e t o Pr h e s 4 throlu h l e 2} e gases are heated to 600 C. in the preheaters, mixed in'a m e 5 and h n n ert t"? syn e s et? the rese c of a atal p e ed b sp k i a s sits h an u ou s lu i n f nickel n trate h tal ii taining about 3% of nickel, at a pressure "of'a boutd atmq rzh eh rea ti n h mb r isii f a y in r cal part 6 abont 1.5 in length and a conical top part 9 fi d to whi h s e mixer 5 or i hs ss qbe' eted- Pa t 6 o he r n h mbe s a a n'j ha ts 8 9 the a qet lys bn mete n ei h and} en ee of this, a further charge 7 of granular magnesite with a layer height of 15 centimeters. The ga s mixtur epasses' throughthe reaction chamber in a downward direction, the synthesis gas formed leaving the chamber through line 10. The reaction temperature is ahout 950 C. at the lower end of the catalyst layer. 400 cubic meters (N. T. P.) of synthesis gas of the following composition are obtained:

Percent by volume Connected to line 2 through which the oxygen is fed into the mixer is line 12 fitted with valve 11 of square millimeters free cross section for steam of 13 atmospheres. The free space 9 houses a thermocouple 13 which functions as a signaler for the steam valve 11. If a flame forms in the mixing chamber, the temperature rises rapidly at the measuring point. When a certain temperature value is reached, valve 11 opens and the steam passes into line 2 and puts the flame out in less than 5 seconds. The "valve recloses in less than half a minute. The catalytic conversion of methane to synthesis gas is not interfered with by this short addition of steam;

The invention is hereby claimed as follows:

1. In a process for the production of acetylene by ,interacting methane with a limited amount of oxygen which is insufiicient for the complete combustion of the methane wherein the methane and the oxygen are separately preheated, mixed in a mixing zone and interacted in a reaction zone With the formation of a flame and the reaction gases are quenched with water, the improvement 'which comprises stopping a premature reaction of the methaneoxygen mixture in the mixing zone while continuing'the 4 the complete combustion of the methane wherein the methane and the oxygen are separately preheated, mixed in a mixing zone and interacted in a reaction zone in the presence of a catalyst consisting of magnesite containing about 3% by weight of nickel, the improvement which comprises stopping a premature reaction of the methaneoxygen mixture in the mixing zone while continuing the flow of methane and oxygen into said mixing zone by introducing into the oxygen stream for a period shorter tha'n'45 seconds at least 100% by volume of steam with reference'to the volume of the oxygen."'

3. In a process of interacting a hydrocarbon gas with a limited amount of oxygen which is insufiicient for the flow of methane and oxygen into said mixin'gizone' by j introducing into theoxygen stream for a periodshorter than 4 seconds at least 40% by volume of nitrogen with reference to the volume of the oxygen. r

2. .In a process for the production of mixtures 0 .carbon monoxide and hydrogen by interacting methane .with a limited amount of oxygen which is insufiicientpfor complete combustion of said hydrocarbon gas and in which said hydrocarbon gas saidsaid oxygenare'separately preheated, mixed in'a mixing zone and interacted in a reaction zone, the improvement which comprises continuously introducing said preheated hydrocarbon gas and said oxygen into said' mixing zone'and interacting said hydrocarbon gas and oxygen in a reaction zone, and stopping intermittent, premature'interactionof the mixture of said hydrocarbon gas and said oxygen, while continuing feed of hydrocarbon gas and oxygen into the mixing zone, by introducing an inert gas' in sufiicient quantity'to stop said premature interaction in the mixing zone when said interaction occurs and ceasing'the introduction of said quantity of said inert gas into the mixing zone when'said premature interaction has stopped. 4.The process of claim 3 wherein the inert gas is mixed with the preheated oxygen prior'to introduction of said oxygen into said mixing zone. SLTh'e process of claim 3 wherein the inert gas is 6. The process of claim 3 wherein the inert gas is steam. 7. The'process'of claim 3 wherein the inert gas'is carbon dioxide.

8. The process of claim 3 wherein the introduction of said inert gas into said mixing zone is initiated automatically in response to an increase in pressurein said mixingzone brought about by the premature interaction of the mixture of said hydrocarbon gas and said oxygen in said mixing zone. i

9. The process of claim 3 wherein the introduction of said inertgas'into said mixing zone is initiated automatically in response to an increase in temperature 'in said mixing zone broughtabout by the prematurein'te'raction of the mixture'of saidhydrocarbon ga's andsaid Oxygen in said mixing zone."

References Cited in the file of this patent UNITED STATES PATENTS 

1. IN A PROCESS FOR THE PRODUCTION OF ACETYLENE BY IN TERACTING METHANE WITH A LIMITED AMOUNT OF OXYGEN WHICH IS INSUFFICIENT FOR THE COMPLETE COMBUSTION OF THE METHANE WHEREIN THE METHANE AND THE OXYGEN ARE SEPARATELY PREHEATED, MIXED IN A MIXING ZONE AND INTERACTED IN A REACTION ZONE WITH THE FORMATION OF A FLAME AND THE REACTION GASES ARE QUENCHED WITH WATER, THE IMPROVEMENT WHICH COMPRISES STOPPING A PREMATURE REACTION TO THE METHANE- 